The Federal Communications Commission has paved the way for AT&T to finally use spectrum for its 4G LTE network that had been sidelined for 15 years because it caused interference with satellite radio services.

At its open meeting today, which was Webcast for the public, the FCC approved a compromise proposal that had been submitted by AT&T and Sirius XM Radio earlier this year that protects the satellite radio service by instituting unused guard bands of spectrum that are right next to the spectrum that Sirius uses.

All five of the commissioners on the FCC supported the proposal.

AT&T

AT&T has been buying spectrum on the secondary market from companies to help it meet the demands of its customers. The company, like many other wireless providers, says it needs more wireless spectrum to handle growing demand for wireless data services. AT&T owns about 20MHz spectrum in the 2.3 GHz Wireless Communications Service, or WCS band. But the company has been unable to use this spectrum because of interference issues with the neighboring satellite radio service. In June, AT&T and Sirius filed a joint proposal to the FCC that the companies said would alleviate the problems. The companies were asking the FCC to change some of its rules on how the spectrum is allocated so that they could avoid interference.

Specifically, the solution calls for AT&T to divide its 20 MHz of WCS spectrum into four 5 MHz channels. AT&T has agreed to not use the two 5 MHz slivers of wireless spectrum closest to the spectrum Sirius uses. That 10 MHz of spectrum will be a buffer to help avoid interference.

AT&T will be giving up half the spectrum it has in this band. But given that it took 15 years for the wireless and satellite industries to agree on a solution to this problem, it's easy to understand why AT&T would be willing to sacrifice some spectrum as a guard band.

During a press conference that was Webcast after the meeting, FCC Chairman Julius Genachowski admitted that the commission had intervened and pressed AT&T and Sirius to come up with a solution on their own.

"This is a very proactive commission," he said. "When we see problems, we go out and fix them. And the team did a tremendous job in the work leading up to today's order."

"The era of regulatory dispute and uncertainty in the WCS band is finally drawing to a close," Joan Marsh, AT&T vice president of federal regulatory, said in a blog post. "Today, in a unanimous vote, the FCC approved an order adopting the joint proposal filed by AT&T and Sirius XM designed to bridge long-standing differences in the band to reach mutually-acceptable solutions and to position the WCS band for mobile broadband deployment."

Marsh went on to emphasize that AT&T has taken "real risks to develop this under-utilized band and is committed to devoting the resources necessary to unlock its full potential."

She said that AT&T will begin deploying LTE service using this spectrum in about three years.

In addition to developing a process for a new wireless spectrum auction set for 2014, the FCC is also looking for other ways to free up additional wireless spectrum. It is currently reviewing a proposal from satellite TV provider Dish Network to repurpose its spectrum in the 2GHz band so that it can be used for wireless broadband service. Dish owns 40 MHz of spectrum it hopes can be used for 4G LTE services. It's unclear whether Dish would offer this service on its own, or if it would sell the spectrum once repurposed to a wireless carrier, such as AT&T.

The FCC said in March when it kicked off the review process that it expected to conclude its review by the end of the year. During the press conference, Genachowski reiterated that timeline.